The company TRUMPF, 71254 Ditzingen, Germany, offers a mechanical system under the name TLC® 1005 for the cutting, welding and surface treatment of metallic workpieces by laser. That system is available with an automatic pallet changing system. Pallets of the pallet changing system with workpieces placed thereon are fed to the working area of the system prior to workpiece processing. When processing is complete, the pallets with the then processed workpieces are moved out of the working area of the system. Each pallet has its own drive unit. The drive means used are floor-mounted endlessly circulating toothed belts. When several pallets are used to service the working area of the system, the individual pallets may be movable in the same axial direction or in axial directions running perpendicular to one another.
EP 0 781 626 A1 discloses a table changing device for a machine for processing workpieces. At a processing unit for processing metallic workpieces two workpiece tables are moved alternately into a loading and unloading position, on the one hand, and into a processing position, on the other hand. For that purpose the workpiece tables are attached to two endless drive chains, each circulating with a top strand and a bottom stand. Stationary chain driving wheels, which are seated on the drive shaft of a likewise stationary drive motor, are used to drive the endless drive chains.
The workpiece table drive system disclosed in EP 0 781 626 A1 and described above occupies a relatively large amount of space and forms an interference contour which is constantly present and which may hinder functional use of the prior-known arrangement.